Variable pitch propeller



May, 26, 1942. w. J. FIKE VARIABLE PITCH PROPELLER 2 Sheets-Sheet 1 Filed Feb. 6, 1.941

May 26, 1942. v w J F|-KE 2,284,516

VARIABLE PITCH PROPELLER Filed Feb. 6, 1941 2 Sheets-Sheet 2 Patented May 26, 1942 UNITED STATES PATENT OFFICE VARIABLE PITCH PROPELLER William I. Fike, Pavillion, Wyo.

Application February 6, 1941, Serial No. 377,756

Claims.

This invention relates to a novel variable pitch propeller for aeroplanes and more particularly to a propeller having a hollow hub portion in which a pair of propeller blades are journaled and having gear means connecting the inner ends of the blades to a member disposed within the hub and adapted to be actuated by the movement of centrifugal weights for increasing the pitch of the blades as the speed of rotation of the hub member increases.

Still another aim of the invention is to provide spring means adapted to operate in conjunction with the pressure of air on the propeller blades for reducing the pitch of the blades when the speed of rotation of the propeller is diminished sumciently so that the force exerted by the spring means and the pressure of air on the propeller blades is sufllcient to overcome the force exerted by the centrifugally operated Weights.

Still a further aim of the invention is to provide manually operative means capable of being operated from the cabin of an aeroplane equipped with the propeller for manually increasing or reducing the pitch of the propeller blades to vary the pitch of the blades to obtain the maximum efllciency under different flying conditions such as taking on, climbing and cruising.

Still a further aim of 'the invention is to provide a variable and constant speed propeller of very simple design and construction which may be manufactured and sold at a much lower price than devices for the same purpose now on the market, which can be easily operated and controlled, and which may be readily applied to replace a conventional propeller and which will require very few changes in the engine to adapt it for use with the variable pitch propeller.

Still another aim of the invention is to provide a construction of variable pitch propeller which can be controlled manually or automatically.

Other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, which illustrate a preferred embodiment thereof, and wherein:

Figure 1 is a transverse central sectional view, partly in elevation, of the variable pitch propeller,

Figure 2 is a vertical sectional view taken substantially along the plane of the line 2-2 of Figure 1,

Figure 3 is a transverse central sectional view 3-3 of Figure 2, and at right angles to Figure 1, Figure 4 is a front elevational view of the same with the detachable forward section of the hub housing removed, and

Figure 5 is a sectional view taken substantially along the plane of the line 55 of Figure 1.

Referring more particularly to the drawings,

wherein like reference characters designate like or corresponding parts throughout the diii'erent views, It designates a portion of the forward end of the cowling of an aeroplane from which projects a crankshaft II.

-The variable pitch propeller, designated generally l2, and comprising the invention, includes a hub, designated generally I3, having a centrally disposed sleeve portion It for engaging the crankshaft ii and which is adapted to be keyed thereto in any conventional manner, not shown. The crankshaft II is provided with a restricted threaded outer end It for receiving a nut it which engages the outer end of the sleeve member H for retaining it in position on the crankshaft The sleeve member l4, adjacent its rear end, is provided with an integral outwardly projecting housing section II which is provided with a forwardly curved outer portion which terminates in an outwardly projecting flange". A removable housing section I! is provided with a central opening 20 for engaging a restricted portion 2| in the forward end of the sleeve member H. The housing section It is curved rearwardly and toward the housing section I! and is provided with a flange 22 at its outer end which abuts against the flange l8 and which is attached thereto by means of nut and bolt fastenings 23 which extend through alined openings 24 in the flanges I8 and 22. The shape of the hub housing is clearly illustrated in Figure 2. The housing sections l1 and I! are provided with diametrically opposed outwardly bowed semicircular portions 25, as seen in Figures 1, 2 and 4, having inwardly opening circumferentially disposed grooves 28 for receiving anti-friction bearing means 21..

A pair of corresponding socket members 2| are journaled in'the bores 29 of the hub housing formed by the complementary portions 25, and are provided with flanges ill at their inner ends and with inwardly tapered bores 3| which extend longitudinally therethrough and which are preferably polygonal shaped in cross section. A pair of propeller blades 32, portions only of which are illustrated, are provided with tapered taken substantially along the plane'of the line po y o a s ped a k ds 3 sized d s aped The gear segments-33 each extend through an I are of approximately 90 degrees or one-quarter of a circle.

The sleeve member H, as best seen in Figure 3,

is provided with substantially straight outwardly opening grooves 31 which are disposed in dismetrically opposed relationship and transversely of its circumference. A ring 38 is turnably mounted on the portion of the sleeve member I4 which is provided with the grooves 3'1 and is provided with slots 39 which are disposed at angles of approximately 30 degrees to the grooves 31. A collar 40 is loosely mounted on the ring 33 and is provided with diametrically opposed threaded openings 4| for receiving the threaded shank portions ofstuds 42 which are provided,

with restricted shank ends '43 which extend through the slots 39 and into thegrooves 31 which are complementary thereto. It will thus be apparent that the collar 40 is prevented from rotating relatively to the sleeve member l4 but can slide relatively thereto and a sliding motion of the collar 43 will cause the studs 42 to slide relatively to the slots 39 for imparting a rotating motion to the ring 38. Ring 38 is provided with diametrically opposed beveled gear segments 44 at its inner end which are substantially the same length as the gear segments 36 and which are arranged to mesh therewith,as best seen of the ring 33 will cause the sockets 28 and the propeller blades 32 to revolve relatively to the hub l3 to vary the pitch of the propeller blades 32.

Referring particularly to Figures 1 and 4, sleeve member i4. adjacent its outer end, is

provided with diametrically opposed flat por-' tions 45 forming continuations of the restricted portion 2| and which are adapted to receive the intermediate portions of bars 46 which are secured thereto by means of nut and bolt fastenings 41 which extend through openings 46 on opposite coil spring 58. The opposite ends of the contractile coil springs 53 are connected to apertured enlargements 53 on the forward end of the collar 40. The collar 46 is provided with diametrically opposed extensions 63 at its forward end which extend into the spaces between the complementary ends of the bars 46 and which bear against the rear edges of the ends 53.

Rods 6| extend through and are loosely disposed in openings 62 in the housing portion l1 and are provided with forward, inner threaded ends which engage threaded sockets 63 in the rear end of the collar 43. The opposite, outer ends of the rods 6| are secured to a thrust "colhr 34 which is disposed on the outerside of wardly curved free ends 63 for loosely engaging the'groove 65. A crank arm 10 is keyed to one end of the shaft 66 and has. a rod ll pivotally connected to its opposite, free end. The rod II telescopes into a tube 12 and is provided with a pin 13 which extends transversely therethrough and the ends of which project therefrom for slidably engaging diametrically opposed longitudinal slots 14 in the tube 12. The tube 12 is -adapted to extend into the cabin of the aeroin Figures 1 and 5 so that a turning movement '40 plane and to be connected to suitable means, not shown, such as a lever by means of which a reciprocating motion can be imparted to the parts 'H and 12 for actuating the shaft 66 and the crank arms 68 for moving the thrust collar 64 toward and away from the hub I3 to move the collar 46 forwardly and rearwardly of the ring 38.

If the engine of the aeroplane, not shown, is operating at a constant throttle opening the speed of rotation of the propeller l2 will vary depending upon the pitch of the blades 32 and sides of the shaft H and through alined openings in the'bars 46, seen in dotted lines at 49. Nut and bolt fastenings 50 extend through alined openings adjacent the ends of the bars 46 for engaging the sleeves 5| which are tumably mounted thereon between the complementary ends of the bars 46 and which are formed integral with the apexes of the angular arms 52.

The arms 52 are provided with short ends 53 which extend inwardly of one another and the longer ends 54 which are normally disposed in substantially parallel relationship to one another and to the sleeve member l4 and which are provided with weights 55 at their freeends and intermediate of the front and rear of the hub housing and in the fenlargedhiametrically opposed recessed portions 56 thereof which. portions are substantially at right angles to the bore portions 29.

- Referring particularly. to Figures 1 and 4, the ,.,nut and bolt fastenings41,'at opposite ends thereofrcarryclips '51 having eyelets in each of which is"conne'cted aniendoi ;a -contractile 75 will increase as the pitch of the blades is decreased or decrease when the pitch of the blades is increased. For maximum efficiency, the pitch of the blades should be slight when the aeroplane is taking off in ascending as the load on the engine is greater under such conditions and. it is therefore preferable to have the engine turning over as fast as possible. In cruising, where the load on the engine is greatly reduced for greater efflciency the pitch of the propeller blades should be increased so that the maximum I the position that the parts will assume when the shaft H is not rotating. When the shaft II is revolved, the weights 55 will be swung outwardly by centrifugal force to cause the ends 53 of the arms 52 to swing rearwardly and due to the fact that the portions 60 of the collar 46 are in engagement with the rear side or edges of the ends 53 the collar 43 will be moved rearwardly to actuate the parts, as previously described, to increase the pitch of the propeller blades proportionately with the increase in the speed of rotation of the shaft I I. However, the propeller blades offer greater wind resistance as their pitch is increased and the airimpinging upon the propeller blades therefore has a tendency to reduce their pitch which tendency must be overcome by the centrifugal force exerted by the weights 55. Also, the contractile coil springs 58 tend to draw the collar 40 forwardly and against the action of the weights 55 for reducing the pitch of the blades 32 and the pressure of the springs 55 will coact with the energy produced by the air impinging upon the propeller blades to reduce the pitch when the speed of rotation of the shaft II is reduced so that the action oi the centrifugal weights 55 will be oflset by the springs 58 and the air on the blades 32 and conversely to maintain the blades 32 at a correct pitch for the most eflicient operation, assuming that the weight and size of theweights 55 and the tension and force of the springs 58 are correctly proportioned. It

will thus be seen that under normal flying con-,

ditions the blades 32 will be automatically maintained at a proper pitch for the most eflicient operation of the. aeroplane.

However, for taking off and ascending it is necessary to manually reduce the pitch of the blades 32 and this is accomplished by the link H, 12 being moved rearwardly to the full extent of its movement so that the pin 13 will engage the outer ends of the slots 14 to draw the rod H rearwardly to rock the shaft 56 to move the thrust collar 54 to its forwardmost position in which position the parts are held by the link ll, 12 against the action of the weights 55. Similarly, the blades 32 can be held at a high pitch by moving the linkage connection I I, 12 to an extreme forward position for holding the thrust collar 64 in a rearmost position. when the linkage connection ll, 12' is in an intermediate position the connection 13, ll thereof will permit the collar 54 to move forwardly and rearwardly so that the adjustment of the pitch of the propeller blades 32 can be varied automatically, as previously explained, by the weights 55 and the springs 58.

If desired, the rod II can be secured fast to the tube 12 in which case the propeller l2 can be controlled manually and when so controlled the springs 58 may be omitted and the centrifugal weights 55 employed to counteract the pres-' sure of the air impinging upon the blades 32 so that very little energy will be required to vary the pitch of the blades 32.

Various modifications and changes are contemplated and may obviously be resorted to as only a preferred embodiment of the invention has been disclosed.

I claim as myinvention:

l. A variable pitch propeller for aeroplanes comprising a hollow hub member keyed to a slide longitudinally of the hub and having portions for engaging said arms and to be actuated by the outward movement of the weights, a ring rotatably mounted in the hub, means for conmovement of the collar will cause said ring to be turned, said ring being provided with circumferentially spaced gear segments, said propeller blades being provided with gear segments for meshing with the gear segments of the ring whereby the propeller blades will be turned on their longitudinal axes relatively to the hub by the turning movement of the ring for varying the pitch of the propeller blades, rods slidably mounted in the inner end of said hub, said rods having corresponding ends connected to said collar and opposite ends projecting from the hub, a thrust collar secured to the last mentioned ends of said rods, and manually operable means for engaging and moving the thrust collar in one direction for turning said ring in one direction.

2. A variable pitch propeller comprising a hollow hub member having a centrally disposed sleeve portion keyed to a driven shaft, propeller blades having their inner, ends journaled in the hub member, said sleeve portion having substantially straight transversely disposed outwardly opening grooves, a ring turnably mounted on the grooved portion of the sleeve member and pro-.

vided with slots disposed at an angle to said grooves, a collar loosely mounted on said ring and provided with studs extending through said slots and into said grooves, said ring being provided with circumferentially spaced gear segments, said blades being provided with gear segments for meshing with the gear segments of the ring, manually operative means connected to said collar for sliding it relatively to the sleeve member for rotating the ring to turn the blades on their longitudinal axes for varying the pitch of the blades, arms pivotally mounted in the hub member and having free ends provided with weights adapted to be swung outwardly by the centrifugal force caused by the rotation of the hub member, and said arms being provided with angularly disposed extensions for engaging said collar for moving it in one direction relatively to the ring for turning the ring in a direction for increasing the pitch of the propeller blades.

3. A variable pitch propeller comprising a hollow hub member having a centrally disposed sleeve portion keyed to a driven shaft, propeller blades having their inner ends Journaled in the hub member, said sleeve portion having substantially straight transversely disposed outwardly opening grooves, a ring turnably mounted on the grooved portion of the sleeve member and provided with slots disposed at an angle to said grooves, a collar loosely mounted on said ring and provided with studs extending through said slots and into said grooves, said ring being provided with circumferentially spaced gear segments, said blades being provided with gear 0e8- ments for meshing with the gear segments of the ring, manually operative means connected to said collar for sliding it relatively to the sleeve member for rotating the ring to turn the blades on their longitudinal axes for varying the pitch of the blades, said manually operative means comprising rods connected to said collar and extending through and slidably mounted in the inner side of the hub member, a thrust collar secured to the rods and disposed on the outer side of the hub member and provided with an annular inwardly opening groove, and link memnecting said ring and collar whereby the sliding bers loosely engaging the groove in the thrust collar and adapted to be manually actuated for moving the thrust collar toward and away from the hub member for actuating the first mentioned collar.

4. A variable pitch propeller comprising a hollow hub member having a centrally disposed sleeve portion keyed to a driven shaft, propeller blades having their inner ends joumaled .in the hub member, said sleeve portion having substantially straight transversely disposed outwardly opening grooves, a ring turnably mounted on the grooved portion 01' the sleeve member and provided with slots disposed at an angle to said grooves, a collar loosely, mounted on said ring and provided with studs extending through said slots and into said grooves, said ring being provided with circumferentially spaced gear segments, said blades being provided with gear segments for meshing with the gear segments of the ring, manually operative means connected to said collar for sliding it relatively to the sleeve member for rotating the ring to turn the blades on their.. longitudinal axes for varying thepitch of the blades, spring means connected to:said collar for urging it in a direction for turning the ring in a direction to reduce the pitch of the propeller blades.

5. A variable pitch propeller comprising a hollow hub member having a centrally disposed sleeve portion keyed to a'ldriven shaft, propeller blades having their inner ends journaled-in the hub member said sleeve portion having substantially straight transversely disposed outwardly opening grooves, a ring turnably mounted on the grooved portion of the sleeve member and provided with slots disposed at an angle to said grooves, a collar loosely mounted on said ring and provided with studs extending through said slots and into said grooves, said ring being provided with circumferentially spaced gear segments, said blades being provided with gear segments for meshing with the gear segments of the ring, manually operative means connected to said collar for sliding it relatively to the sleeve member for rotatingthe ring to turn the blades on their longitudinal axes for varying the pitch of the blades, centriiugally actuated weights for engaging the collar to urge it in one direction for turning the ring in a direction to increase the pitch of the propeller blades, and spring means for urging the collar in the opposite direction.

WILLIAM J. FIKE. 

